spi: bitbang: switch to the generic implementation of transfer_one_message
Change the bitbang driver to use the generic implementation of transfer_one_message. This simplifies the bitbang driver code and provides benefits like the statistics in the generic implementation. Successfully tested on a IMX6-based system (spi-imx) and on a MIPS-based router (OpenWRT with spi-ath79). Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Heiner Kallweit
Mark Brown
parent
e30d8f2392
commit
0037686596
1 changed files with 36 additions and 89 deletions
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@ -24,6 +24,8 @@
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#include <linux/spi/spi.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/spi/spi_bitbang.h>
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#define SPI_BITBANG_CS_DELAY 100
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/*----------------------------------------------------------------------*/
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/*----------------------------------------------------------------------*/
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@ -265,100 +267,28 @@ static int spi_bitbang_prepare_hardware(struct spi_master *spi)
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}
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}
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static int spi_bitbang_transfer_one(struct spi_master *master,
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static int spi_bitbang_transfer_one(struct spi_master *master,
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struct spi_message *m)
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struct spi_device *spi,
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struct spi_transfer *transfer)
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{
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{
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struct spi_bitbang *bitbang;
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struct spi_bitbang *bitbang = spi_master_get_devdata(master);
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unsigned nsecs;
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int status = 0;
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struct spi_transfer *t = NULL;
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unsigned cs_change;
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int status;
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struct spi_device *spi = m->spi;
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bitbang = spi_master_get_devdata(master);
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if (bitbang->setup_transfer) {
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status = bitbang->setup_transfer(spi, transfer);
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if (status < 0)
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goto out;
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}
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/* FIXME this is made-up ... the correct value is known to
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if (transfer->len)
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* word-at-a-time bitbang code, and presumably chipselect()
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status = bitbang->txrx_bufs(spi, transfer);
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* should enforce these requirements too?
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*/
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nsecs = 100;
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cs_change = 1;
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if (status == transfer->len)
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status = 0;
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list_for_each_entry(t, &m->transfers, transfer_list) {
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if (bitbang->setup_transfer) {
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status = bitbang->setup_transfer(spi, t);
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if (status < 0)
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break;
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}
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/* set up default clock polarity, and activate chip;
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* this implicitly updates clock and spi modes as
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* previously recorded for this device via setup().
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* (and also deselects any other chip that might be
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* selected ...)
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*/
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if (cs_change) {
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bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
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ndelay(nsecs);
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}
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cs_change = t->cs_change;
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if (!t->tx_buf && !t->rx_buf && t->len) {
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status = -EINVAL;
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break;
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}
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/* transfer data. the lower level code handles any
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* new dma mappings it needs. our caller always gave
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* us dma-safe buffers.
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*/
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if (t->len) {
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/* REVISIT dma API still needs a designated
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* DMA_ADDR_INVALID; ~0 might be better.
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*/
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if (!m->is_dma_mapped)
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t->rx_dma = t->tx_dma = 0;
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status = bitbang->txrx_bufs(spi, t);
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}
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if (status > 0)
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m->actual_length += status;
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if (status != t->len) {
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/* always report some kind of error */
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if (status >= 0)
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status = -EREMOTEIO;
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break;
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}
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status = 0;
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status = 0;
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else if (status >= 0)
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status = -EREMOTEIO;
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/* protocol tweaks before next transfer */
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out:
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if (t->delay_usecs)
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spi_finalize_current_transfer(master);
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udelay(t->delay_usecs);
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if (cs_change &&
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!list_is_last(&t->transfer_list, &m->transfers)) {
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/* sometimes a short mid-message deselect of the chip
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* may be needed to terminate a mode or command
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*/
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ndelay(nsecs);
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bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
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ndelay(nsecs);
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}
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}
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m->status = status;
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/* normally deactivate chipselect ... unless no error and
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* cs_change has hinted that the next message will probably
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* be for this chip too.
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*/
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if (!(status == 0 && cs_change)) {
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ndelay(nsecs);
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bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
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ndelay(nsecs);
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}
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spi_finalize_current_message(master);
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return status;
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return status;
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}
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}
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@ -376,6 +306,22 @@ static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
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return 0;
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return 0;
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}
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}
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static void spi_bitbang_set_cs(struct spi_device *spi, bool enable)
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{
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struct spi_bitbang *bitbang = spi_master_get_devdata(spi->master);
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/* SPI core provides CS high / low, but bitbang driver
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* expects CS active
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* spi device driver takes care of handling SPI_CS_HIGH
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*/
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enable = (!!(spi->mode & SPI_CS_HIGH) == enable);
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ndelay(SPI_BITBANG_CS_DELAY);
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bitbang->chipselect(spi, enable ? BITBANG_CS_ACTIVE :
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BITBANG_CS_INACTIVE);
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ndelay(SPI_BITBANG_CS_DELAY);
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}
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/*----------------------------------------------------------------------*/
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/*----------------------------------------------------------------------*/
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/**
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/**
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@ -424,7 +370,8 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)
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master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
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master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
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master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
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master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
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master->transfer_one_message = spi_bitbang_transfer_one;
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master->transfer_one = spi_bitbang_transfer_one;
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master->set_cs = spi_bitbang_set_cs;
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if (!bitbang->txrx_bufs) {
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if (!bitbang->txrx_bufs) {
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bitbang->use_dma = 0;
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bitbang->use_dma = 0;
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